A neat boss idea (high level, side boss)

So I've had an idea for a sweet side boss lately. For this boss, it would be recommended you are at least level 90. He does cheat. He would be a side boss found in a dungeon with powerful monsters. The instance would be repeatable for more glorious loot if desired. He also knows spells from all schools.

Dialogue would be something like this:- "So this is what the wizards of this age were like, not as reformed and refined as I am."- "I was once like you, part of the light, but now I am more powerful than you can imagine!"- "I have mastered all magic schools, you have little chance of success against me."- "Let's see how the wizards of this age can hold against a wizard of old!"

Cheats:- "I am more powerful than you can imagine!" Attempting to use negative charms on him trigger this cheat. (including dispels and multi-hit attacks like plague) He casts a unique spell called "Seven Stars" Spells that leave negative charms do not trigger this cheat.Spell: Seven Stars: Deal 500 ,,,,, & damage to target. (Think extreme hydra or Chimera)- "You are not refined like I am!" Attacks under 1000 trigger this. He casts a unique spell called "Phase Change"Spell: Phase Change: 500 + 1200 damage over three rounds & remove all positive charms.- "Your new age spells are no match!" Casting universal shields and absorbs trigger this cheat. (He doesn't know balance attacks) He casts a unique spell called "Solar Storm"Spell: Solar Storm: 890 damage to all & remove all positive wards.- "I'm part of the light too!" Casting a shadow polymorph triggers this. He casts a unique spell called "Gradient Change"Spell: Gradient Change: Cancel target shadow polymorph and deal 500 damage.